The proposed studies will be directed toward finding - in fresh tissues, short-term cultures of human prostatic tissues, and secretions - the presence of oncogenic RNA viruses or their expressed functions. To this end, we will use biochemical and electron microscopic methods to detect extracellular or intracellular particles with characteristics analogous to known oncornaviruses of other species: simultaneous RNA and "reverse transcriptase" content, buoyant density properties, as well as ultrastructural definitions. We will also attempt to detect intracellular high molecular weight RNA (60-70S) containing long polyriboadenylate-rich regions. In addition, we will study whether potent "reverse-transcriptase" inhibitors have any differential effects on the in vitro rates of DNA synthesis in normal and malignant tissues. Our overall aim will be to delineate any differences between cells - or cellular products obtained from "low-risk" and "high-risk" groups based on age and histologic appearances (e.g. a comparison of benign hypertrophy and carcinoma of the prostate). Positive findings would have far reaching implications for the etiology of human prostatic cancer and for new practical approaches for the prevention and possible treatment of neoplastic diseases. In addition, our studies may provide insight by delineating hormonal or age-related factors which modulate production of viral functions in a human tissue under subtle hormonal balance.